“Since the photographer's picture was not conceived but selected, his subject was never truly discrete, never wholly self-contained. The edges of his film demarcated what he thought most important, but the subject he had shot was something else; it had extended in four directions. If the photographer's frame surrounded two figures, isolating them from the crowd in which they stood, it created a relationship between those two figures that had not existed before.”
John Szarkowski, The photographer’s Eye